Follow press conferences throughout the week. Generally the team will give the media an idea of where they're going.
Watch the lines. Denver -8 hosting Indy? Just doesn't look right at all. Would most likely stay away from that game, for an example.
Look at playoff scenarios. Pitt has clinched homefield throughout as well as a 1st round bye. No need to play anyone. However, some teams don't want players getting rusty....for example, Vick looks to play this week for Atl, after not playing last week.